ORIGINAL PAPER Homobimetallic complexes of ligand having O- and S-donor sites with same and different di- and trialkyl/aryltin(IV) moiety: their synthesis, spectral characterization and biological activities M. Jabeen • S. Ali • S. Shahzadi • M. Shahid • Q. M. Khan • S. K. Sharma • K. Qanungo Received: 25 June 2011 / Accepted: 12 September 2011 / Published online: 3 January 2012 Ó Iranian Chemical Society 2011 Abstract Homobimetallic complexes with oxygen and sulphur donor ligand have been synthesized at room tem- perature under stirring conditions using R 2 SnCl 2 (R = Me, n-Bu) and R 3 SnCl (R = Me, n-Bu, Ph) in 1:1 molar ratio. The synthesized complexes have been characterized by elemental analysis, IR and multinuclear NMR ( 1 H, 13 C) spectroscopy. These complexes have also been screened for their biological activities. IR data show that the ligand acts in a bidentate manner and exhibits trigonal bipyra- midal geometry in solid state which is also confirmed by semi-empirical study. NMR data show that reported com- plexes exhibit tetrahedral geometry in solution. Results of antimicrobial screening activities indicated that complexes (6) and (7) are very effective antibacterial and antifungal agents, respectively, and they might indeed be a potential source of antimicrobial agents, while the complex (3) exhibits significant free radical scavenging ability with lower IC 50 value of 99.47 ± 1.2 lg/mL. Results of cyto- toxicity/haemolytic activity showed the significant value of % haemolysis for complex (7) (18.101 ± 2.3), while complex (4) was found to be least cytotoxic (5.733 ± 1.0). Only a few colonies are observed in mutagenicity testing by Ames test. Keywords Homobimetallic complexes  IR  NMR  Semi-empirical study  Antimicrobial  Cytotoxic  Antioxidant  Mutagenic Introduction In recent years, considerable progress has been made in the synthesis, characterization and application of organotin compounds. A large number of organotin compounds are used as pharmaceuticals, pesticides, stabilizers and fire retardants [1, 2]. Tin has a large number of organometallic derivatives that have wide agricultural and industrial applications [3, 4]. Several organotin compounds exhibit promising in vitro anti-tumour activities against human tumour cell lines [5]. The chemistry of organotin(IV) complexes has devel- oped considerably during the last 30 years. Organotin compounds in general and organotin carboxylates in par- ticular continue to be developed because of their biological activity and use as potential antineoplastic and antituber- culosis agents [6], PVC stabilizers [7] and anti-tumour drugs [8] as well as polymer catalysts [9]. Organotin(IV) compounds are mostly used as biocides and in industry M. Jabeen  S. Shahzadi (&) Department of Chemistry, GC University, Faisalabad, Pakistan e-mail: sairashahzadi@hotmail.com S. Ali (&) Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan e-mail: drsa54@yahoo.com M. Shahid Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad, Pakistan Q. M. Khan Environmental Biotechnology Division, NIBGE, P.O. Box 577, Jhang Road, Faisalabad, Pakistan S. K. Sharma  K. Qanungo Department of Applied Science and Humanities, Faculty of Engineering and Technology, Mody Institute of Technology and Science (Deemed University), Lakshmangargh, District Sikar 332311, Rajasthan, India 123 J IRAN CHEM SOC (2012) 9:307–320 DOI 10.1007/s13738-011-0025-8